Walmart, Costco, Kohl's, Apple and Ikea top the list of 25 corporations that have a combined total of 445 megawatts of solar capacity, representing a 48 percent increase over the deployed commercial solar amongst the top 25 companies in 2012.

Together, the top 25 corporations using solar energy are generating enough electricity to power 734,000 average American homes.

The nearly 50 percent increase in investment is in line with corporate trends toward sustainability and indicates the maturity of the solar industry.

“For years, the promise of solar was always 'just around the corner,'” said Adam Browning, Executive Director of Vote Solar. “Well, solar has turned the corner, and found itself on Main Street, USA. These companies – titans of American business – may have vastly different products, business models, and geographic locations, but they all have something in common: They know a good deal when they see one, and they are going solar in a big way."

Walmart alone has 89 megawatts of installed solar at 215 different locations throughout the country, making the retail giant the nation’s largest private employer and also the country’s single biggest corporate solar investor.

“As we work toward our ambitious goal to be supplied 100 percent by renewable energy, solar energy continues to be an important part of our renewable energy portfolio,” stated Walmart’s Vice President of Energy, Kim Saylors-Laster. “With our size and scale, Walmart is in a unique position to encourage innovation and accelerate the adoption of cost-effective, clean energy alternatives, including solar power.”

The companies that are investing the most in solar have engrained sustainability into the fabric of their operations and have found solar to be one of the most effective ways to reduce energy expenses, as well as greenhouse gas emissions.

“The list of companies moving to clean, affordable solar energy reads like a ‘Who’s Who’ of the most successful corporations in America,” SEIA President and CEO Rhone Resch added. “These iconic brands are leading the way when it comes to efforts to reduce our nation’s dangerous dependence on foreign energy sources. They’re also helping to create thousands of American jobs, boost the U.S. economy and improve our environment.”

It's important to note that the top 25 corporations deploying solar are just leading the pack. Commercial solar deployment climbed more than 40 percent in 2013, to a total of 3,380 megawatts.